As one of the core techniques in the future ubiquitous wireless communication, the UWB wireless communication technique has attracted wide attention in recent years, and its development has made remarkable progress.
The way to realize UWB technique can be generally divided into two basic implementation mode of impulse system and carrier wave system. The impulse system UWB transmits information by using baseband pulse sequence, has the advantages of simple system structure, low cost, low power consumption and the like, and has gained a wide range of applications in wireless communication, distance measurement, exploration fields; on the other hand, carrier wave system UWB, by using mature modulated continuous carrier wave and Orthogonal Frequency Division Multiplexing (OFDM) technology, etc., has gained high efficiency in spectrum utilization and flexibility in using spectrum resources. Under the impulse system UWB technology, the receiving end can use peak detection, energy detection, simulation correlation detection methods etc., hence its processing performance is restricted by simulation manipulation and generally only a lower speed wireless communication, exploration, positioning and other functions can be realized; the receiving end can also use high speed sampling methods and perform digital processing through low-precision quantification, hence it has the advantages of stable performance and easy integration, and can achieve a higher speed in wireless transmission.
In impulse-UWB of high speed sampling system, one of the difficulties is to achieve synchronization. In the existing synchronization method, it obtains estimation on synchronization position by using the periodic or pseudorandom characteristics of synchronization sequence and by performing energy correlation or sliding correlation on the sampled data. However, in the impulse-UWB system, since the sampling rate is extremely high, it can only carry out the quantification of the sampled value with low precision at one bit or two bits and produces large quantification noises due to the constraints on power consumption and processing capacity of the system, and hence the above-mentioned existing synchronization method can no longer be used. In this situation, a feasible method is to estimate the channel impulse response through the accumulation of multiple periodic signals, and to search the peak position of channel estimation in the cumulative process and to take this peak position as the synchronization reference position. This method is a sliding cumulative process and needs large amounts of calculation; further, because the peak position cannot be determined instantaneously, it is necessary to check over a long enough period of time before the determination can be reached, hence resulting in the need for large storage space and causing delay in processing.